Use of hydrogen scavenging catalysts to control polymer molecular weight and hydrogen levels in a polymerization reactor

Abstract

The present invention provides dual catalyst systems containing a metallocene catalyst and a hydrogen scavenging catalyst, and polymerization processes employing these dual catalyst systems. Due to a reduction in hydrogen levels in the polymerization processes, olefin polymers produced from these polymerization processes may have a higher molecular weight, a lower melt index, and higher levels of unsaturation.

1. An olefin polymerization process, the process comprising:
 contacting a catalyst composition with an olefin monomer and optionally an olefin comonomer under polymerization conditions to produce an olefin polymer, wherein the catalyst composition comprises catalyst component I, catalyst component II, an activator-support, and an organoaluminum compound, wherein: 
 catalyst component I comprises a metallocene compound; 
 catalyst component II comprises a hydrogen scavenging catalyst; and 
 a molar ratio of catalyst component I to catalyst component II in the catalyst composition is in a range from about 40:1 to about 10,000:1. 
 
     
     
       2. The process of  claim 1 , wherein catalyst component I comprises:
 a compound having formula (C); 
 a compound having formula (D); or 
 any combination thereof, wherein: 
 
       formula (C) is 
       
         
           
           
               
               
           
         
       
       wherein:
 M 3  is Zr or Hf; 
 X 4  and X 5  are independently F; Cl; Br; I; methyl; benzyl; phenyl; H; BH 4 ; OBR 2  or SO 3 R, wherein R is an alkyl or aryl group having up to 18 carbon atoms; or a hydrocarbyloxide group, a hydrocarbylamino group, or a hydrocarbylsilyl group, any of which having up to 18 carbon atoms; 
 E 3  is a bridging group selected from:
 a cyclic or heterocyclic bridging group having up to 18 carbon atoms, 
 a bridging group having the formula >E 3A R 7A R 8A , wherein E 3A  is C or Si, and R 7A  and R 8A  are independently H or a hydrocarbyl group having up to 18 carbon atoms, 
 a bridging group having the formula —CR 7B R 8B —CR 7C R 8C —, wherein R 7B , R 8B , R 7C , and R 8C  are independently H or a hydrocarbyl group having up to 10 carbon atoms, or 
 a bridging group having the formula —SiR 7D R 8D —SiR 7E R 8E —, wherein R 7D , R 8D , R 7E , and R 8E  are independently H or a hydrocarbyl group having up to 10 carbon atoms; 
 
 R 9  and R 10  are independently H or a hydrocarbyl group having up to 18 carbon atoms; and 
 Cp 1  is a cyclopentadienyl or indenyl group, any substituent on Cp 1  is H or a hydrocarbyl or hydrocarbylsilyl group having up to 18 carbon atoms; and 
 
       formula (D) is 
       
         
           
           
               
               
           
         
       
       wherein:
 M 4  is Zr or Hf; 
 X 6  and X 7  are independently F; Cl; Br; I; methyl; benzyl; phenyl; H; BH 4 ; OBR 2  or SO 3 R, wherein R is an alkyl or aryl group having up to 18 carbon atoms; or a hydrocarbyloxide group, a hydrocarbylamino group, or a hydrocarbylsilyl group, any of which having up to 18 carbon atoms; 
 E 4  is a bridging group selected from:
 a cyclic or heterocyclic bridging group having up to 18 carbon atoms, 
 a bridging group having the formula >E 4A R 12A R 13A , wherein E 4A  is C or Si, and R 12A  and R 13A  are independently H or a hydrocarbyl group having up to 18 carbon atoms, 
 a bridging group having the formula —CR 12B R 13B —CR 12C R 13C —, wherein R 12B , R 13B , R 12C , and R 13C  are independently H or a hydrocarbyl group having up to 10 carbon atoms, or 
 a bridging group having the formula —SiR 12D R 13D —SiR 12E R 13E —, wherein R 12D , R 13D , R 12E , and R 13E  are independently H or a hydrocarbyl group having up to 10 carbon atoms; and 
 
 R 14 , R 15 , R 16 , and R 17  are independently H or a hydrocarbyl group having up to 18 carbon atoms. 
 
     
     
       3. The process of  claim 1 , wherein the hydrogen scavenging catalyst comprises Ru, Rh, Pt, Pd, Fe, Ni, Nb, Ti, or a combination thereof. 
     
     
       4. The process of  claim 1 , wherein catalyst component II comprises: 
       
         
           
           
               
               
           
         
       
       a compound having the formula 
       
         
           
           
               
               
           
         
       
       or any combination thereof, wherein:
 M 5  is Zr or Hf; 
 X 8  and X 9  are independently F; Cl; Br; I; methyl; benzyl; phenyl; H; BH 4 ; OBR 2  or SO 3 R, wherein R is an alkyl or aryl group having up to 18 carbon atoms; or a hydrocarbyloxide group, a hydrocarbylamino group, or a hydrocarbylsilyl group, any of which having up to 18 carbon atoms; 
 Cp 2  and Cp 3  are independently a cyclopentadienyl or indenyl, any substituent on Cp 2  and Cp 3  is independently H or a hydrocarbyl group having up to 18 carbon atoms; and 
 E 5  is a bridging group having the formula —(CH 2 ) n —, wherein n is an integer from 2 to 8, inclusive. 
 
     
     
       5. The process of  claim 1 , wherein the molar ratio of catalyst component I to catalyst component II in the catalyst composition is in a range from about 50:1 to about 1000:1. 
     
     
       6. The process of  claim 1 , wherein the hydrogen scavenging catalyst has a hydrogen removal activity greater than about 5,000 moles of hydrogen (H 2 ) per mole of the hydrogen scavenging catalyst per hour. 
     
     
       7. The process of  claim 1 , wherein:
 a weight-average molecular weight (Mw) of the olefin polymer produced by the process is from about 10% to about 500% greater than a weight-average molecular weight (Mw) of an olefin polymer obtained under the same polymerization conditions without catalyst component II; or 
 a melt index (MI) of the olefin polymer produced by the process is from about 15% to about 95% less than a MI of an olefin polymer obtained under the same polymerization conditions without catalyst component II; or 
 a high load melt index (HLMI) of the olefin polymer produced by the process is from about 15% to about 95% less than a HLMI of an olefin polymer obtained under the same polymerization conditions without catalyst component II; or 
 any combination thereof. 
 
     
     
       8. The process of  claim 1 , wherein:
 a melt index of the olefin polymer produced by the process is in a range from about 0.1 to about 5 g/10 min; or 
 a density of the olefin polymer produced by the process is in a range from about 0.89 to about 0.96 g/cm 3 ; or 
 an average total polymer unsaturation per chain of the olefin polymer produced by the process is in a range from about 1.01 to about 50; or 
 any combination thereof. 
 
     
     
       9. The process of  claim 1 , wherein an average total polymer unsaturation per chain of the polymer produced by the process is in a range from about 1.5 to about 20. 
     
     
       10. The process of  claim 1 , wherein the polymerization process is conducted in the presence of hydrogen at a liquid phase hydrogen concentration in a range from about 0.1 ppm to about 5000 ppm. 
     
     
       11. The process of  claim 1 , wherein the activator-support comprises a solid oxide treated with an electron-withdrawing anion, wherein:
 the solid oxide comprises silica, alumina, silica-alumina, silica-coated alumina, aluminum phosphate, aluminophosphate, heteropolytungstate, titania, zirconia, magnesia, boria, zinc oxide, a mixed oxide thereof, or any mixture thereof; and 
 the electron-withdrawing anion comprises sulfate, bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate, fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate, fluorozirconate, fluorotitanate, phospho-tungstate, or any combination thereof. 
 
     
     
       12. The process of  claim 1 , wherein the activator-support comprises fluorided alumina, chlorided alumina, bromided alumina, sulfated alumina, fluorided silica-alumina, chlorided silica-alumina, bromided silica-alumina, sulfated silica-alumina, fluorided silica-zirconia, chlorided silica-zirconia, bromided silica-zirconia, sulfated silica-zirconia, fluorided silica-titania, fluorided silica-coated alumina, sulfated silica-coated alumina, phosphated silica-coated alumina, or any combination thereof. 
     
     
       13. The process of  claim 1 , wherein the organoaluminum compound comprises trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminum chloride, or any combination thereof. 
     
     
       14. The process of  claim 1 , wherein the catalyst composition further comprises an aluminoxane compound, an organoboron or organoborate compound, an ionizing ionic compound, or any combination thereof. 
     
     
       15. The process of  claim 1 , wherein the process is conducted in a batch reactor, slurry reactor, gas-phase reactor, solution reactor, high pressure reactor, tubular reactor, autoclave reactor, or a combination thereof. 
     
     
       16. The process of  claim 1 , wherein the olefin monomer is ethylene, and the olefin comonomer comprises propylene, 1-butene, 2-butene, 3-methyl-1-butene, isobutylene, 1-pentene, 2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 2-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene, 1-octene, 1-decene, styrene, or a mixture thereof. 
     
     
       17. A catalyst composition comprising catalyst component I, catalyst component II, and an activator, wherein:
 catalyst component I comprises a metallocene compound; 
 catalyst component II comprises a hydrogen scavenging catalyst; and 
 a molar ratio of catalyst component I to catalyst component II in the catalyst composition is in a range from about 40:1 to about 10,000:1, and wherein: 
 catalyst component I comprises:
 a compound having formula (C); 
 a compound having formula (D); or 
 any combination thereof, wherein: 
 
 
       formula (C) is 
       
         
           
           
               
               
           
         
       
       wherein:
 M 3  is Zr or Hf; 
 X 4  and X 5  are independently F; Cl; Br; I; methyl; benzyl; phenyl; H; BH 4 ; OBR 2  or SO 3 R, wherein R is an alkyl or aryl group having up to 18 carbon atoms; or a hydrocarbyloxide group, a hydrocarbylamino group, or a hydrocarbylsilyl group, any of which having up to 18 carbon atoms; 
 E 3  is a bridging group selected from:
 a cyclic or heterocyclic bridging group having up to 18 carbon atoms, 
 a bridging group having the formula >E 3A R 7A R 8A , wherein E 3A  is C or Si, and R 7A  and R 8A  are independently H or a hydrocarbyl group having up to 18 carbon atoms, 
 a bridging group having the formula —CR 7B R 8B —CR 7C R 8C —, wherein R 7B , R 8B , R 7C , and R 8C  are independently H or a hydrocarbyl group having up to 10 carbon atoms, or 
 a bridging group having the formula —SiR 7D R 8D SiR 7E R 8E —, wherein R 7D , R 8D , R 7E , and R 8E  are independently H or a hydrocarbyl group having up to 10 carbon atoms; 
 
 R 9  and R 10  are independently H or a hydrocarbyl group having up to 18 carbon atoms; and 
 Cp 1  is a cyclopentadienyl or indenyl group, any substituent on Cp 1  is H or a hydrocarbyl or hydrocarbylsilyl group having up to 18 carbon atoms; and 
 
       formula (D) is 
       
         
           
           
               
               
           
         
       
       wherein:
 M 4  is Zr or Hf; 
 X 6  and X 7  are independently F; Cl; Br; I; methyl; benzyl; phenyl; H; BH 4 ; OBR 2  or SO 3 R, wherein R is an alkyl or aryl group having up to 18 carbon atoms; or a hydrocarbyloxide group, a hydrocarbylamino group, or a hydrocarbylsilyl group, any of which having up to 18 carbon atoms; 
 E 4  is a bridging group selected from:
 a cyclic or heterocyclic bridging group having up to 18 carbon atoms, 
 a bridging group having the formula >E 4A R 12A R 13A , wherein E 4A  is C or Si, and R 12A  and R 13A  are independently H or a hydrocarbyl group having up to 18 carbon atoms, 
 a bridging group having the formula —CR 12B R 13B —CR 12C R 13C —, wherein R 12D , R 13B , R 12C , and R 13C  are independently H or a hydrocarbyl group having up to 10 carbon atoms, or 
 a bridging group having the formula —SiR 12D R 13D —SiR 12E R 13E —, wherein R 12D , R 13D , R 12E , and R 13E  are independently H or a hydrocarbyl group having up to 10 carbon atoms; and 
 
 R 14   9 R 15 , R 16 , and R 17  are independently H or a hydrocarbyl group having up to 18 carbon atoms; 
 catalyst component II comprises: 
 
       
         
           
           
               
               
           
         
       
       a compound having the formula 
       
         
           
           
               
               
           
         
       
       or any combination thereof, wherein:
 M 5  is Zr or Hf; 
 X 8  and X 9  are independently F; Cl; Br; I; methyl; benzyl; phenyl; H; BH 4 ; OBR 2  or SO 3 R, wherein R is an alkyl or aryl group having up to 18 carbon atoms; or a hydrocarbyloxide group, a hydrocarbylamino group, or a hydrocarbylsilyl group, any of which having up to 18 carbon atoms; 
 Cp 2  and Cp 3  are independently a cyclopentadienyl or indenyl, any substituent on Cp 2  and Cp 3  is independently H or a hydrocarbyl group having up to 18 carbon atoms; and 
 E 5  is a bridging group having the formula —(CH 2 ) n —, wherein n is an integer from 2 to 8, inclusive; and 
 the activator comprises an activator-support, an aluminoxane compound, an organoboron or organoborate compound, an ionizing ionic compound, or any combination thereof. 
 
     
     
       18. An olefin polymerization process comprising contacting the catalyst composition of  claim 17  with an olefin monomer and optionally an olefin comonomer under polymerization conditions to produce an olefin polymer.